DJ's mid chart question - bar height during practice runs

[wjsawyer]

I started using the mid mark chart last year and felt it really improved my full approach vaults.

We've started using the chart for short approach runs (4 lefts). I'm holding lower on softer poles than from my full approach. For example, yesterday I was holding at 12'3" with a 6 stride mark at 41'. The corresponding bar height is 12' but when we put a bungee here it feels too low and I usually don't have good top end form because it isn't needed to clear the bungee.

It seems like the calibration between bar height and the rest of the chart doesn't hold as well when doing short approach work. When a vaulter does a short approach run they 'scale down' their grip height and speed as indicated on the chart, but do not 'scale down' their vertical jump, strength, etc that is used from a full approach - thus making for a higher vault than the chart would indicate.

In my mind it is better to have a bungee up too high (making you reach for it and work on top end technique) than too low (letting you relax your top end and get sloppy). Is it OK to put a bungee up 1' or 2' higher than indicated by the chart for short approach vaults?

[dj]

The grip to bar height is for the average jumper with a PR bar height near that height.

If your overall PR is much higher you will have swing and plant skills that are above the average for that grip and bar height...

Don't know if that makes since...

The idea at any run distance is to maximize the run - plant and swing technique.. Raising the bar fits the challenge...

Good work

Dj

[wjsawyer]

Thanks for the answers DJ. its nice to have the creator himself back up my intuitive interpretation of his work.

Just out of curiosity, can you elaborate on how you gathered data for the grip height/bar height relationship? Who do you consider an 'average' vaulter for each height? High school level, collegiate?

-Will

[dj]

The chart was actually not created from a lot of "gathered data"..

I was a long jumper in the late 60's and had learned that the basic "physics" of the event was:

The Faster you could run on the runway, all other parts being equal, the farther you could p jump.

Fast AND "accurate" was the basic elements and to be fast and accurate you needed to be an "exact" distance from the board, based on the speed you were or could run (stride length x stride frequency = speed. The faster you were the longer the strides) for me, six steps from the board was my "check" point and 44-6 to 45 feet was my distance in the long jump so that I wouldn't stretch or have to chop and slow/steer too much. A friend and fellow competitors mark was 45-6 to 26 feet. When we had tailwinds of course we ran faster and moved back. My PR was 25, his 26+. I formed a "physical/physics "relationship" with these numbers. Add 20 feet to someone's/anyone's PR and you had a very good idea where there check mark should be.

In 1971 I was vaulting in the decathlon and coaching a little bit and felt it was as important to have a
accurate and fast run in the pole vault as it was in the LJ. So I looked at the relationship between the six step marks from several 14 foot vaults compared those to several 16 foot vaults.

The first "concept" in the vault is "the faster you can run the higher you can hold", which should produce higher vaults.

To be accurate and fast the same that held true (physics of speed) in the long jump should hold true in the vault. That said, a physical/physics/mathematical relationship should/would be evident for a six step check point. That check point would be based on speed and that speed would have a direct relationship to hand grip and hand grip would have a direct relationship to "average" height vaulted.

So my first "chart" started with
14-0 bar……. 13-5 grip…….45 foot six step mark
………………………………………………………………………….
…………………………………………………………………………..
………………………………………………………………………….
16-0 bar……14-7 grip……..49-0 foot six step mark

When I analyzed the numbers… I got this… (I decided I had better convert to meters to do the math correctly) One foot/30cm of "run" at the six step check mark was worth one hand grip (9cm). Which I had experienced as a vaulter and coach! Raise a hand grip---move back a foot...If I raised my grip I had to run faster, if I ran faster I had to move my step out… right!

So if you look at the differences between a 14 foot vault and a 16 foot vault you have four feet of run and four hand grips—which ended up being 9cm per grip.

From there I filled in the numbers from 14-6 to 15-0 to 15-6… eventually I completed the chart down to 10 feet and up to 19 feet.

Eventually by 1980 I filled in the takeoffs, the speed/MPS needed for each grip and vault and the stride lengths so the vaulters could do pole runs on the track at various lengths to "improve" the approach stride lengths and frequencies.

Tim Mack had a 54-8 six stride mark, a 16-4 grip and jumped 19-6 in 2004. I had the Six Step, grip and speed numbers on my chart 20 years before that vault. The one big thing you will notice about Tim's jumping is that he is "above the norm" in efficiency… the "average" jump by the numbers/physics for a 16-4 grip is 19-0… Tim Jumped over 19-8 several times with that grip.

I have continually "checked" the numbers for the six step "MID", to grip to bar height in every meet and every scientific paper. They have held "true" with the test of time… even Bubka's marks/MID's were "on the chart.

If you run correctly the speeds (length and frequencies) will match so the grip should match. If the speed is there and the grip is low you blow through… if the grip is too high for the correct speed you come up short.

Sorry for a long answer…. Hopefully all can continue to use the chart to help everyone's approach faster and more accurate.

dj